A double-sided image forming device including a mechanism for reversing a paper sheet is disclosed in Patent Documents 1 and 2, for example. In the device disclosed in Patent Document 1, a paper sheet is reversed by performing switchback thereon. Further, in the device disclosed in Patent Document 2, a paper sheet is reversed in a twisting manner. Moreover, other well-known examples of double-sided image forming devices include a device disclosed in Patent Document 3. Besides, well-known examples of mechanisms for reversing paper sheets include devices disclosed in Patent Documents 4 and 5.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 62-280133
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2006-103855
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2003-2547
Patent Document 4: Japanese Unexamined Patent Application Publication No. 63-267640
Patent Document 5: Japanese Unexamined Patent Application Publication No. 11-207927